Hydraulic unit

ABSTRACT

The present invention relates to a hydraulic unit for a hydraulic regulation device, in particular for slip-controlled motor vehicle brake systems, comprising several hydraulic, mechanical and/or electrically operable functional elements arranged at an accommodating member, such as accumulation elements, valve elements, pressure-generation and driving elements, and comprising at least one cavity associated with at least one functional element and disposing of means for bleeding. It is the core of the invention that two connecting channels that lead into the ambience are provided with closing devices, which hinder the ingress of fluid into the cavity and allow ventilation of the cavity and a discharge of leakage fluid into the ambience. The invention permits an automatic bleeding and an automatic removal of leakage fluid independently of the spatial arrangement of the unit.

TECHNICAL FIELD

The present invention relates to a hydraulic unit for a hydraulicregulation device, in particular for slip-controlled motor vehicle brakesystems, comprising several hydraulic, mechanical and electricallyoperable functional elements arranged at an accommodating member, suchas accumulation elements, valve elements, pressure-generation anddriving elements, comprising several pressure fluid channelsinterconnecting the functional elements and capable of providing ahydraulically switchable connection between at least one pressure fluidsource and one pressure fluid consumer, as well as comprising aconnection to a control device for actuating the functional elements,and comprising at least one cavity associated with at least onefunctional element and disposing of means for bleeding.

BACKGROUND OF THE INVENTION

DE 42 39 361 A1 discloses a generic immersion-proof hydraulic unitcomprising a connecting path that leads from the cavity in the directionof free ambience, and including a non-return valve that opens in thedirection of an exhaust of the connecting path. In particular pumps withoscillating pump pistons produce a defined quantity of leakage fluidthat can accumulate in a cavity designed as a crank chamber. The priorart unit allows the discharge of leakage fluid out of the cavity intothe ambience in addition to a bleeding operation. The connecting path isisolated from the ambience in the reverse direction.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a hydraulic unit thatallows the discharge of leakage fluid over the entire useful life of thevehicle in any desired mounting position in the vehicle. Anotherobjective is to prevent the ingress of splash water, dirt, or similarcontaminants into the cavity, even if a hydraulic unit heated in drivingoperations is fully immersed into water (immersion-proof). This isbecause a sudden thermal shock due to immersion of a heated hydraulicunit causes a vacuum in the air-filled cavities. Said vacuum will exertadditional stress on sealing elements so that water can enter theinterior of the unit when the sealing effect is fading. Salt or waterthat enters into the valve chamber, pump chamber, motor compartment, andpressure accumulation chamber will accumulate in and possibly flood thecavities.

The conditions described above can occur in particular in off-roadvehicles, e.g. when the hydraulic unit must be arranged in the area of awheel house due to limited mounting spaces.

This object is achieved by two connecting channels that lead into theambience and are provided with closing devices, which hinder the ingressof fluid into the cavity and allow ventilation of the cavity and adischarge of leakage fluid into the ambience. The invention permits apump-like discharge of leakage fluid and a pressure-compensatingventilation of the unit's interior.

Preferably, the connecting channels include closing devices, whichprincipally adopt a closing position and alternately are movable into anopen position. The valve function does not hinder the passage of mediain the open condition.

According to a preferred embodiment of the invention, the closingdevices are designed as non-return valves movable to adopt an openposition due to a pressure difference between cavity and ambience. Thispermits a leakage discharge in dependence on a pneumatic pressurebalance between inside space and ambience.

According to another preferred embodiment of the invention, a closingdevice opening in the direction of the cavity is associated with a firstconnecting channel so that pressure compensation in the cavity takesplace due to the passage of atmospheric air. The closing device preventsair from escaping out of the cavity. Associated with a second connectingchannel is a closing device, which opens in the direction of theambience and through which air and/or leakage fluid is discharged intothe ambience.

Favorably, an air-permeable and fluid-impermeable diaphragm isassociated with the closing device of the first connecting channel. Saiddiaphragm prevents the ingress of fluid when the unit is immersed, evenif a vacuum in the interior of the unit opens the closing device. Thediaphragm does not hinder the passage of air for the purpose of pressurebalance.

Further, it is advantageous that the air-permeable and fluid-impermeablediaphragm is arranged in front of the closing device in the forwarddirection.

In an embodiment of the invention favorable for the assembly, theair-permeable and fluid-impermeable diaphragm in combination with theclosing device is provided as a modular unit and attached to a componentof the hydraulic unit.

According to another embodiment of the invention, the connectingchannels open into accommodating bores for the closing devices, saidclosing devices being inserted into the accommodating bores in aform-fit or frictionally engaged manner. This permits a simplifiedarrangement or bores in the accommodating member and a simple assemblystarting from the outside surfaces of the accommodating member.

In another design of the invention, each closing device includes asupporting body with apertures for a medium as well as an attachmentseat and a preferably conical sealing seat, wherein the attachment seatincludes a groove into which an elastic diaphragm with a bead ismounted, and wherein a sealing lip of the diaphragm bears against thesealing seat in an elastically biased fashion. The result is that theclosing device can be handled and mounted as an independent modularunit.

The need for a separate seal is obviated when the diaphragm has acylindrical design and includes an annular outside wall for the purposeof sealing between the accommodating member and the supporting body.Besides, a guiding effect for the diaphragm is achieved when the latterincludes a generally plane bottom with a central recess penetrated by apeg of the supporting body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic sketch for illustrating the invention.

FIG. 2 is a partly cross-sectional top view of an embodiment of ahydraulic unit.

FIG. 3 is an enlarged view of the detail characterized by A in FIG. 2.

FIG. 4 is an enlarged view of the detail characterized by B in FIG. 2.

FIG. 5 is a state-of-the-art hydraulic unit according to DE 42 39 361A1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 5 depicts a hydraulic unit 1 for a controlled brake systemcomprising an electric motor 2 with a motor housing. The electric motor2, as is apparent, is attached to an accommodating member 3 thatincludes several hydraulic, mechanical and electrically operablefunctional elements (not shown). These functional elements primarilyconcern accumulation elements, valve elements, and pressure generationelements, and several pressure fluid channels interconnecting thefunctional elements so that a switchable connection between a pressurefluid source and a pressure fluid consumer can be established. Further,an electronic control unit 11 for the valves is attached to theaccommodating member 3.

An eccentric 5 arranged at a motor shaft 4 projects into an inner spaceof the accommodating member 3 configured as cavity 6. Said eccentric 5is used to drive a hydraulic piston pump with oscillating pump pistons.An outside ring 7 of the bearing which is unrotatable relative to theaccommodating member 3 is seated on the eccentric 5 pivoted by way of aroller bearing, said ring 7 performing an eccentric movement due to theeffect of the eccentric 5. The outside ring 7 of the bearing acts onpistons (not shown), which are displaceably provided in bores in theaccommodating member that are arranged vertically to the drawing plane.The outside bearing ring 7 and the eccentric 5 rotate in the cavity 6designed as crank chamber.

Leakage fluid stripped by the pump pistons accumulates in the cavity 6,namely at the cavity's deepest point, and propagates through an opening8 into a connecting channel 9 that leads into the ambience. A closingdevice 10 that opens in the direction of the ambience in the way of anon-return valve is provided in the connecting channel 9. Accumulatedleakage fluid may be discharged out of the cavity 6 into the ambientatmosphere U due to an opening movement of the non-return valve. Saidleakage fluid can exit reliably only if the hydraulic unit 1 is mountedin the vehicle in a mounting position exhibiting a connecting channel 9that points downwards. If this is not the case, accumulated leakagefluid can cause higher losses.

The basic principle of the invention can be taken from FIG. 1. Featurescorresponding with FIG. 5 have been designated with identical referencenumerals. An air-filled cavity 6 is connected to the ambience U by wayof two connecting channels 9, 12. Associated with each of the connectingchannels 9, 12 is a closing device 10, 13 that principally, that meansin the non-actuated condition, adopts a closing position. FIG. 1 showsin this context non-return valves that include spring-loaded closingmembers 14, 15 being pressed against a sealing seat 16, 17. It is clearthat other elastic resetting means, in particular those according toFIG. 3 and FIG. 4, may also be provided without departing from thespirit of the invention. As can be seen, the closing devices 10, 13 aremovable into an open position as a result of the difference in pressurebetween the ambience U and the cavity 6. As this occurs, a closingdevice 13 opening in the direction of cavity 6 is associated with theconnecting channel 12 so that a pressure balance in the cavity 6 ispossible due to the passage of atmospheric air. Associated with theconnecting channel 9 is a closing device 10 which opens in the directionof the ambience U. When pressure in excess of the atmospheric pressure(in relation to the ambience) prevails in the cavity 6 and thedifference in pressure is sufficient to open the closing device 10, airand possibly accumulated leakage fluid is discharged from the interiorof the unit, that means, out of the cavity 6. Closure takes placeautomatically after the pressure balance. The connecting channel 9 canbe arranged in any optional mounting position in the vehicle inconsequence of the active discharge operation.

An air-permeable and fluid-impermeable diaphragm 18 is arranged in frontof the closing device 13 of the connecting channel 12. Said diaphragmprevents fluid from entering the cavity 6 in the immersed condition,also when an increased water pressure prevails. On the other hand,diaphragm 18 allows pressure compensation with the ambience U shouldvacuum (in relation to the ambience) develop in the cavity 6, and if theeffective pressure difference is sufficient to open the closing device13.

Constructive details of an embodiment of a hydraulic unit can be takenfrom FIGS. 2, 3 and 4. Components or features corresponding to FIGS. 1and 5 have been assigned identical reference numerals. The motor 2 withthe motor housing is attached to the top side of the accommodatingmember 3. A housing for an electronic control device 11 for theelectromagnetically operable valves is disposed on a bottom sideopposite to the top side. A plug terminal is used to connect the controldevice 11 to an electric/electronic wiring system for communication andcurrent supply purposes. The current supply of the motor extends throughthe accommodating member. If the motor 2 is not sealed completely withrespect to the accommodating member 3, the cavity 6 communicates with aninner space of the motor 2. This communication may e.g. take placethrough a small radial gap between a brush holder plate (not shown) andthe motor shaft 4.

The connecting channels 9, 12 shown only partly in FIG. 2 respectivelyopen with one end into the cavity 6 and with another end intoaccommodating bores 20, 21 for the closing devices 10, 13. Bothconnecting channels 9, 12 are placed in one plane with a preferablycontinuous bore for the pump pistons. Reference numeral Z designates theaxis of the pump pistons in FIG. 2. A certain offset positioning of theaxes of opposite bores for pump pistons, i.e. a certain offset betweenthe pump pistons, is possible. The pistons' movements extend in parallelin each case. The connecting channels 9, 12 extend in a directionvertical to the drawing plane. Both closing devices 10, 13 are arrangedin the area of different lateral surfaces 22, 23 of the accommodatingmember 3 provided at right angles relative to each other. When theclosing devices are arranged opposite each other at opposed lateralsurfaces 23, 24 or 22, 25, the connecting channels 9, 12 can be machinedas a through-bore in one operating cycle. A bore extending in parallelto the axis A is especially expedient because it is possible to machineit in a processing station.

Each closing device 10, 13 is inserted from outside into the associatedaccommodating bore 20, 21 during assembly and attached therein inpositive or operative engagement. In general, clinching of theaccommodating member 3 or a clinched attachment due to the installationmovement of the closing devices 10, 13 is also feasible for attachment.

FIG. 3 and FIG. 4 showing embodiments of closing devices 10, 13 of thediaphragm type will be explained in more detail in the following. Eachclosing device 10, 13 is designed as an independently operable modularunit and comprises a supporting body 26, 27 disposing of at least oneaperture 28, 29 for a medium or a mix of media, i.e. air or anair/leakage fluid mix. Instead of a spring-biased closing member, anelastic diaphragm 30, 31 is attached to the supporting body 26, 27 and,in the non-actuated condition, bears with a sealing lip 32, 33 in anelastically preloaded fashion against a sealing seat 34, 35 close to thesupporting body so that the passage of media is closed. As can be takenfrom the drawings, the sealing seats 34, 35 have a conical design. Eachelastic diaphragm 30, 31 comprises a substantially plane bottom with acentral recess through which a peg 36, 37 close to the supporting bodyextends for guiding purposes. As FIG. 3 shows, the elastic diaphragm 30extends over a fastening portion of the supporting body 26 at least inpart and is mounted with a bead 38 in a groove of the supporting body26.

The closing device 13 according to FIG. 3 accommodates the diaphragm 18on the ambience side being permeable to air yet impermeable to moistureand particles. Said diaphragm 18 is preferably made of a plastic such asPTFE in particular.

In the closing device 10 according to FIG. 4, the elastic diaphragm 31extends over a fastening portion of the supporting body 27. A bead 39extends over an end of the supporting body 27.

As a protection against damages, the closing devices 10, 13 respectivelycomprise on the outside surface a cover 40, 41 including recesses.

1-9. (canceled)
 10. Hydraulic unit for a hydraulic regulation device, inparticular for slip-controlled motor vehicle brake systems, comprisingseveral hydraulic, mechanical and electrically operable functionalelements arranged at an accommodating member, especially accumulationelements, valve elements, pressure-generation and driving elements,comprising several pressure fluid channels interconnecting thefunctional elements and capable of providing a hydraulically switchableconnection between at least one pressure fluid source and one pressurefluid consumer, as well as comprising a connection to a control devicefor actuating the functional elements, and comprising at least onecavity associated with at least one functional element and disposing ofmeans for bleeding, wherein two connecting channels that lead into theambience are provided with closing devices, which hinder the ingress offluid into the cavity and allow ventilation of the cavity and adischarge of leakage fluid into the ambience.
 11. Hydraulic unit asclaimed in claim 10, wherein the connecting channels include closingdevices, which principally adopt a closing position, and in that theclosing devices alternately are movable into an open position. 12.Hydraulic unit as claimed in claim 10 with connecting channels thatinclude closing devices, which principally adopt a closing position, andthe closing devices alternately are movable into an open position,wherein the closing devices are designed as non-return valves movable toadopt an open position as a result of a pressure difference betweencavity and ambience.
 13. Hydraulic unit for a hydraulic regulationdevice, in particular for slip-controlled motor vehicle brake systems,comprising several hydraulic, mechanical and electrically operablefunctional elements arranged at an accommodating member, especiallyaccumulation elements, valve elements, pressure-generation and drivingelements, comprising several pressure fluid channels interconnecting thefunctional elements and capable of providing a hydraulically switchableconnection between at least one pressure fluid source and one pressurefluid consumer, as well as comprising a connection to a control devicefor actuating the functional elements, and comprising at least onecavity associated with at least one functional element and disposing ofmeans for bleeding, and two connecting channels that lead into theambience are provided with closing devices, which hinder the ingress offluid into the cavity and allow ventilation of the cavity and adischarge of leakage fluid into the ambience wherein a closing deviceopening in the direction of the cavity is associated with the firstconnecting channel so that pressure compensation in the cavity takesplace due to the passage of atmospheric air, and wherein associated withthe second connecting channel is a closing device, which opens in thedirection of the ambience and through which air and/or leakage fluid isdischarged into the ambience.
 14. Hydraulic unit as claimed in claim 13,wherein an air-permeable and fluid-impermeable diaphragm is associatedwith the closing device of the first connecting channel.
 15. Hydraulicunit as claimed in claim 13, having an air-permeable andfluid-impermeable diaphragm which is associated with the closing deviceof the first connecting channel, wherein the air-permeable andfluid-impermeable diaphragm is arranged in front of the closing devicein the forward direction.
 16. Hydraulic unit as claimed in claim 15,wherein the air-permeable and fluid-impermeable diaphragm in combinationwith the closing device is provided as a modular unit and is attached toa component of the hydraulic unit.
 17. Hydraulic unit as claimed inclaim 10, wherein the connecting channels open into accommodating boresfor the closing devices, and in that the closing devices are insertedinto the accommodating bores in a form-fit or frictionally engagedmanner.
 18. Hydraulic unit as claimed in claim 13, wherein the closingdevice opening in the direction of the ambience is positioned at theaccommodating member in such a fashion that a weight of a definedquantity of accumulated leakage fluid invokes an opening movement of thediaphragm.